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Mallory
High

Next.js next-resume Connection Exhaustion DoS

IdentifiersCVE-2026-44579CWE-400

CVE-2026-44579 is a denial-of-service vulnerability in Next.js affecting versions before 15.5.16 and 16.2.5. It impacts applications using Partial Prerendering via the Cache Components feature. Crafted POST requests to a server action can trigger a request-body handling deadlock associated with the Next-Resume mechanism used for resuming Partial Prerendered requests. In affected configurations, the deadlock leaves connections open for an extended period instead of completing or failing promptly, causing accumulation of open connections and file descriptor consumption until the service becomes unavailable to legitimate users.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

A remote attacker can repeatedly send crafted POST requests that cause connections to remain open for extended periods, exhausting file descriptors and server capacity. The practical result is denial of service against the affected Next.js application, preventing legitimate users from being served. The issue is described as connection exhaustion rather than code execution or data compromise.

Mitigation

If you can’t patch tonight, do this now.

If immediate upgrade is not possible, block externally supplied requests containing the Next-Resume header before they reach Next.js, for example at the edge, reverse proxy, WAF, or load balancer. Because the header is intended to be internal-only, rejecting or stripping it from untrusted client traffic reduces exposure. Additional rate limiting and connection/request timeout controls may help reduce DoS impact, but the primary mitigation in the provided content is blocking the Next-Resume header from external clients.

Remediation

Patch, then assume compromise.

Upgrade Next.js to a fixed release: 15.5.16 or later on the 15.x branch, or 16.2.5 or later on the 16.x branch. According to the provided advisory context, the fix treats the header used for resuming Partial Prerendered requests as internal-only and strips it from untrusted incoming requests.
PUBLIC EXPLOITS

Exploits

No valid public exploits. Mallory filtered out 1 candidate as fakes, detection scripts, or README-only repos.

VALID 0 / 1 TOTALView more in app

All candidate exploits were filtered out by Mallory's validation.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
VercelNextapplication
VercelNext.Jsapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

7 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.

No news coverage yet. Advisories and community discussion only.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity7

Community discussion across Reddit, Mastodon, and other social sources.